Gall Legitimate Discoveries

1

cortex as functioning tissue, not just protective covering ("cortex" is literally "bark" or "skin")

2

commissures (or connecting pathways) between brain hemispheres, other than the already known corpus callosum

3

crossing of ascending nerve pathways from spinal cord to contralateral hemispheres of the brain

4

distribution of and distinction between grey matter and white matter tracts (where grey matter was recognized in the 20th century as mostly neuron cell bodies doing information processing, and white matter as mostly myelinated axons sending signals over longer distances)